Background Inflammatory markers have been shown to be elevated in acute coronary syndromes. Recently, interleukin-6 was demonstrated to be elevated in unstable angina compared with stable angina. However, the effect of percutaneous coronary interventions on the levels of inflammatory markers is less well known.

Methods and Results In this study, we measured the levels of interleukin-6 and interleukin-1 by using enzyme-linked immunosorbent assays in patients with angina pectoris undergoing coronary interventions and in healthy control subjects. Interleukin-6 was significantly elevated in patients with unstable angina compared with patients with stable angina (P = .01). There were no significant differences between the levels of interleukin-1 in patients with unstable angina versus patients with stable angina and healthy control subjects. Furthermore, at 1-month follow-up after percutaneous coronary interventions, there were no longer any significant differences between the levels of interleukin-6 in patients with unstable angina versus patients with stable angina and healthy control subjects.

Conclusions These data suggest that interleukin-6 levels may correlate with instability of atheromatous plaques and that the decrease of interleukin-6 levels after percutaneous coronary interventions may represent plaque reendothelialization and stabilization. (Am Heart J 1998;136:357-61.)